Fiber optic sensor guided navigation for vascular visualization and monitoring

ABSTRACT

A method for visualizing branches of a lumen includes inserting ( 402 ) a fiber optic shape sensing device into a lumen and determining ( 404 ) changes in the lumen based upon strain induced in the fiber optic shape sensing device by flow in the lumen. Locations of branches are indicated ( 410 ) on a rendering of the lumen. An instrument is guided ( 414 ) to the locations of branches indicated on the rendering.

This disclosure relates to medical instruments and more particularly toshape sensing optical fibers in medical applications for identifying andaccessing branches of a lumen.

Coronary artery bypass grafting (CABG) is a surgical procedure forrevascularization of obstructed coronary arteries. In conventionalsurgery, a patient's sternum is opened and the heart is fully exposed.An important part of this procedure is the removal of a vessel from thepatient's body, which is then used to bypass one or more atheroscleroticnarrowings in the coronary arteries. A vessel most commonly used is theInternal Mammary Artery (IMA) which is located in the chest. Othervessels used include the saphenous vein (leg) and the radial artery(arm).

Minimally invasive (MI) bypass surgery is performed through small ports(e.g., having an opening size of about 5 mm for totally endoscopicprocedures and between about 50-60 mm for MI direct bypass surgery).During MI cardiac bypass surgery, direct access to the vessels used forreplacement in the bypass is not available, and the vessels are removedusing long instruments inserted into ports. During MI surgery, asurgical assistant can hold an endoscope, or the endoscope can be heldusing robotic guidance. In the case of robotic guidance, visual servoingcan be used to move the robot to a specific location. Visual servoingincludes selecting a point on the endoscope image, with the robot movingto maintain the point in the center of the image.

The vessels which are used in cardiac revascularization are oftenembedded in fat and fascia, and for their removal they need to becarefully excised from the surrounding tissue. In addition, the vesselspresent many small branches, which have to be cut and sealed usingstaples or cauterization to avoid leakage through the vessels once thebypass has been performed. This is a very demanding part of theprocedure and is often the most time consuming, especially during MIsurgery. Vision during this part is provided exclusively through anendoscope inserted through a thoracic port. Under these constraints, thebranches can often be missed, leading them to be inadvertently cutwithout being stapled or cauterized in an adequate manner. This can leadto leakage of blood through these side branches, often requiring arepeat revascularization and further surgery.

In accordance with the present principles, a method for visualizing,accessing and/or monitoring branches of a lumen includes inserting afiber optic shape sensing device into a lumen and determining branchesin the lumen based upon strain induced by changes in flow in the lumenin the fiber optic shape sensing device. Locations of branches areindicated on a rendering of the lumen. An instrument is guided to thelocations of branches indicated on the rendering.

In another embodiment, a method for visualizing, accessing and/ormonitoring flow in a branched lumen includes inserting a fiber opticshape sensing device into a lumen; determining a position of the lumenand locations of branches from the lumen based upon changes to flow inthe lumen resulting from strain induced fluctuations measured by thefiber optic shape sensing device; imaging a portion of the lumen toprovide a real-time image; registering the real-time image with theposition of the lumen measured by the fiber optic shape sensing device;and generating an overlay image indicating the position of the lumen andthe locations of branches on the real-time image.

A system for monitoring a blood vessel includes a processor, a memorycoupled to the processor, and a sensing and interpretation module storedin the memory and configured to interpret fiber optic shape sensing datafrom a fiber optic shape sensing device inserted in a blood vesselwherein the shape sensing data determines branches of the blood vessel.An image generation module is stored in the memory and configured togenerate an overlay image based on the fiber optic shape sensing dataindicating a shape of the blood vessel and locations of the branchesfrom the blood vessel. A display is configured to render the overlayimage over a rendering of the blood vessel to provide a guide forfinding and operating on the branches of the blood vessel.

These and other objects, features and advantages of the presentdisclosure will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings.

This disclosure will present in detail the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a block/flow diagram showing a shape sensing system which isemployed for generating an overlay for guiding a surgical tool or devicein accordance with one embodiment;

FIG. 2 is a diagram showing a shape sensing system inserted into a bloodvessel of a patient and an endoscope inserted through a port into thepatient in accordance with one illustrative embodiment;

FIG. 3A is an image showing an internal mammary artery (IMA) taken downthrough a port using an endoscope;

FIG. 3B is an image showing the internal mammary artery (IMA) of FIG. 3Ahaving an overlay image registered thereto in accordance with oneillustrative embodiment; and

FIG. 4 is a flow diagram showing a method for accessing lumen branchesusing optical shape-sensing data in accordance with an illustrativeembodiment.

In accordance with the present principles, systems and methods areprovided that employ Fiber Optic Shape Sensing and Localization (FOSSL)technology to improve and simplify coronary artery bypass grafting(CABG) or other surgical procedures. FOSSL technology or optical fibershape sensing makes optical fibers sensitive to strain and temperature.Surrogate variables such as flow, inflammation, tissuepressure/swelling, tissue contact, etc., can be measured indirectly(using, in the case of flow, for example, temperature gradients ofindicator dilution). The fibers, when embedded in a vessel, can providethe 3D shape and dynamics of the vasculature, as well as flowinformation to help detect branches and bifurcations.

In one embodiment, a procedure is performed using an intraluminallydisposed shape sensing fiber optic device inserted into a vessel to betaken down, e.g., a Left Internal Mammary Artery (LIMA). Athree-dimensional (3D) reconstruction of shape and flow information ofthe vessel (as obtained from shape sensing fiber(s)) is obtained, whichpermits computations for locating of side branches. Registration betweena shape sensing coordinate frame and a robotic endoscope coordinateframe can be made to overlay the vessel to be taken down and itsbranches with shape sensor based 3D reconstruction data on the endoscopeimage. Visual servoing of the robotic endoscope based on selected pointseither on the endoscope image, or points of the 3D shape sensor basedreconstruction can be performed.

It should be understood that the present invention will be described interms of medical instruments for performing bypass surgery or othergrafting procedures; however, the teachings of the present invention aremuch broader and are applicable to any internal procedure. In someembodiments, the present principles are employed in tracking oranalyzing complex biological or mechanical systems. In particular, thepresent principles are applicable to internal tracking procedures ofbiological systems, procedures in all areas of the body such as thelungs, gastro-intestinal tract, excretory organs, blood vessels, etc.The elements depicted in the FIGS. may be implemented in variouscombinations of hardware and software and provide functions which may becombined in a single element or multiple elements.

The functions of the various elements shown in the FIGS. can be providedthrough the use of dedicated hardware as well as hardware capable ofexecuting software in association with appropriate software. Whenprovided by a processor, the functions can be provided by a singlededicated processor, by a single shared processor, or by a plurality ofindividual processors, some of which can be shared. Moreover, explicituse of the term “processor” or “controller” should not be construed torefer exclusively to hardware capable of executing software, and canimplicitly include, without limitation, digital signal processor (“DSP”)hardware, read-only memory (“ROM”) for storing software, random accessmemory (“RAM”), non-volatile storage, etc.

Moreover, all statements herein reciting principles, aspects, andembodiments of the invention, as well as specific examples thereof, areintended to encompass both structural and functional equivalentsthereof. Additionally, it is intended that such equivalents include bothcurrently known equivalents as well as equivalents developed in thefuture (i.e., any elements developed that perform the same function,regardless of structure). Thus, for example, it will be appreciated bythose skilled in the art that the block diagrams presented hereinrepresent conceptual views of illustrative system components and/orcircuitry embodying the principles of the invention. Similarly, it willbe appreciated that any flow charts, flow diagrams and the likerepresent various processes which may be substantially represented incomputer readable storage media and so executed by a computer orprocessor, whether or not such computer or processor is explicitlyshown.

Furthermore, embodiments of the present invention can take the form of acomputer program product accessible from a computer-usable orcomputer-readable storage medium providing program code for use by or inconnection with a computer or any instruction execution system. For thepurposes of this description, a computer-usable or computer readablestorage medium can be any apparatus that may include, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system (or apparatus or device) or apropagation medium. Examples of a computer-readable medium include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), arigid magnetic disk and an optical disk. Current examples of opticaldisks include compact disk read only memory (CD-ROM), compact diskread/write (CD-R/W), Blu-Ray™ and DVD.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1, a system 100 for monitoringa lumen, such as a blood vessel, using shape sensing enabled devices isillustratively shown in accordance with one embodiment. System 100 mayinclude a workstation or console 112 from which a procedure issupervised and/or managed. Workstation 112 preferably includes one ormore processors 114 and memory 116 for storing programs andapplications. Memory 116 may store an optical sensing and interpretationmodule 115 configured to interpret optical feedback signals from a shapesensing device or system 104. Optical sensing module 115 is configuredto use the optical signal feedback (and any other feedback, e.g.,electromagnetic (EM) tracking) to reconstruct deformations, deflectionsand other changes associated with a medical device or instrument 102and/or its surrounding region. The medical device 102 may include acatheter, a guidewire, a probe, an endoscope, a robot, an electrode, afilter device, a balloon device, or other medical component, etc.

Optical sensing module 115 may include models and/or statistical methods140 for evaluating the shape sensing data to provide geometricrelationships and states of the shape sensing device or system 104. Thestatistically methods 140 may include known algorithms adapted toevaluate the shape sensing data to determine flow and othercharacteristics of the structures being evaluated. The shape sensingsystem 104 on device 102 includes one or more optical fibers 126 whichare coupled to the device 102 in a set pattern or patterns. The opticalfibers 126 connect to the workstation 112 through cabling 127. Thecabling 127 may include fiber optics, electrical connections, otherinstrumentation, etc., as needed.

Shape sensing system 104 with fiber optics may be based on fiber opticBragg grating sensors. A fiber optic Bragg grating (FBG) is a shortsegment of optical fiber that reflects particular wavelengths of lightand transmits all others. This is achieved by adding a periodicvariation of the refractive index in the fiber core, which generates awavelength-specific dielectric mirror. A fiber Bragg grating cantherefore be used as an inline optical filter to block certainwavelengths, or as a wavelength-specific reflector.

A fundamental principle behind the operation of a fiber Bragg grating isFresnel reflection at each of the interfaces where the refractive indexis changing. For some wavelengths, the reflected light of the variousperiods is in phase so that constructive interference exists forreflection and, consequently, destructive interference for transmission.The Bragg wavelength is sensitive to strain as well as to temperature.This means that Bragg gratings can be used as sensing elements in fiberoptical sensors. In an FBG sensor, the measurand (e.g., strain) causes ashift in the Bragg wavelength.

One advantage of this technique is that various sensor elements can bedistributed over the length of a fiber. Incorporating three or morecores with various sensors (gauges) along the length of a fiber that isembedded in a structure permits a three dimensional form of such astructure to be precisely determined, typically with better than 1 mmaccuracy. Along the length of the fiber, at various positions, amultitude of FBG sensors can be located (e.g., 3 or more fiber sensingcores). From the strain measurement of each FBG, the curvature of thestructure can be inferred at that position. From the multitude ofmeasured positions, the total three-dimensional form is determined.

As an alternative to fiber-optic Bragg gratings, the inherentbackscatter in conventional optical fiber can be exploited. One suchapproach is to use Rayleigh scatter in standard single-modecommunications fiber. Rayleigh scatter occurs as a result of randomfluctuations of the index of refraction in the fiber core. These randomfluctuations can be modeled as a Bragg grating with a random variationof amplitude and phase along the grating length. By using this effect inthree or more cores running within a single length of multi-core fiber,the 3D shape and dynamics of the surface of interest can be followed.

The device 102 may be inserted into a lumen, e.g., blood vessel 131. Forexample, the blood vessel 131 may include a blood vessel to beharvested, such as, an internal mammary artery (IMA), a saphenous vein,a radial artery or any other suitable blood vessel. A port and/or anincision may be employed to access the interior of the lumen and insertthe device 102 including shape sensing device 104 with sensing fiber(s)126. The shape sensing device 104 collects position data of the bloodvessel 131. This includes the monitoring of motion due to blood flow andtemperature fluctuations due to blood flow. The changes or fluctuationscaused by blood flow can be monitored and/or accumulated over time toprovide a map of branches 162. Statistical methods or models 140 in theoptical sensing module 115 may indirectly compute the locations ofbranches 162 on the blood vessel 131.

In one embodiment, an endoscope or a robotically driven endoscope 150includes a camera 156 mounted thereon for transmitting internal imagesto a display 118. The endoscope 150 and/or the camera 156 may beinserted through a port 158 or incision provided on a patient 160. Theendoscope 150 or the camera 156 includes a coordinate system 152. Theshape sensing device 104 also has its own coordinate system 138. Thesecoordinate systems 138 and 152 can be registered so that data feedbackfrom the shape sensing device can be employed to navigate the endoscopeor robotically driven endoscope 150.

In one example, a registration method performed by or in conjunctionwith a registration module 136 may be employed to register theinformation from the sensing fiber 126 of device 104 onto endoscopeimages 142. In this case, the fiber coordinate frame 138 is registeredto the coordinate frame 152 of the endoscope camera 156, after thecamera 156 has been calibrated. One way to do this would be to point theendoscope 150 at a 3D phantom and then use a 3D reconstruction method(there are many known in art) to reconstruct the surface of the phantom.The sensing fiber 126 could then be used to “brush” over the samephantom surface reconstructing its own 3D shape. Both shapes could thenbe registered by registration module 136 using a method such as, e.g.,an Iterative Closest Point (ICP) method, which is employed to minimizethe difference between two clouds of points. ICP is often used toreconstruct 2D or 3D surfaces from different scans, to co-registeranatomic models, etc. ICP would render the transformation matrix betweenthe two coordinate frames. Other registration methods are alsocontemplated.

During a procedure, the device 102, equipped with the shape sensingdevice 104, is inserted into the blood vessel 131 and accumulatesposition data where the sensing device 104 has been within the vessel131. Dynamic changes are recorded. Dynamic changes may be indirectlymeasured using temperatures differences, blood vessel motion, bloodvessel stiffness, etc. In accordance with the present principles, theshape sensing data obtained by shape sensing device 104 will make iteasier for a surgeon to visualize otherwise hidden branches extendingfrom the vessel 131, as will be described.

Workstation 112 includes the display 118 for viewing internal images ofthe patient 160 with sensing data overlays of the blood vessel 131. Anoverlay image 134 may be generated by an image generation module 148that takes the shape sensing data from the optical sensing module 115and conveys the data dynamically in real-time in the overlay image 134.The overlay image 134 is registered with an endoscopic image 142 takenby camera 156 using the registration module 136. The overlay image 134may include signposts or other indicators to indicate to the surgeon orrobot where the branches 162 exist for the blood vessel 131. As thesurgeon cuts and cauterizes or staples the branches 162, the overlayimage 134 is updated based upon the blood flow data collected by theshape sensing device 104. In this way, the surgeon can easily seewhether there are remaining branches 162 to be dealt with or evenwhether any previously cut branches 162 are still bleeding and needfurther attention.

Once the overlay has been performed, the surgeon can select the branchlocation and a robot 164 can move the endoscope 150 so that the branchlocation is centered in the displayed image (e.g., visual servoing). Inone embodiment, the robot 164 can move the endoscope 150 along the bloodvessel 131 and attend to each branch 162 and ensure that the sealing ofeach branch 162 is complete. In another embodiment, the endoscope 150may move along one side of the artery first and then the other side. Inanother embodiment, a number of branches sensed by optical shape sensingdevice 104 can be displayed on display 118 in the endoscope image 142(for example, a number (or count) of sealed off branches may bedisplayed in the image). As the flow measurement is continuous, thenumber can be updated as the surgeon seals the side branches.

Additionally, the physician can select a branch location on a 3Dpre-operative image (e.g., a CT scan), and the robot 164 can move theendoscope 150 so that the branch is in the center of the endoscope image142. In this case, the physician would select a location on the 3Drepresentation or overlay image 134 of the vessel 131 from the fibersensor (which would include a branch location from flow measurements),and the endoscope 150 would move so that the branch is in the center ofthe image. In this manner, even if the branch is not directly visible,the surgeon knows that it is located underneath the fat and fascia andcan find it with tools.

In another embodiment, a desired graft vessel length and shape can beobtained from pre-operative images, such as X-ray coronary angiograms orCT scans using, e.g., imaging system 110. The preoperative images may becollected in advance by employing imaging system 110 of system 100 or bycollecting the preoperative images at a different location or using adifferent system. During harvesting, a fiber sensor measurement usingshape sensing device 104 can be used to find take-down vessel segmentswhich are ideal given a predetermined vessel-graft wish list. A diametercan be interrogated with the device 104, which is included in aguidewire or other device (102). This acquires point clouds while thedevice 102 with the shape sensing device 104 is being maneuvered in thevessel 131. The spatial extent of points in the cloud would provide anestimate for the take-down vessel diameter.

In yet another embodiment, the shape sensing enabled device 102, e.g., aguidewire, may emit detectable (either visible or near infrared (IR)radiation), which can be detected with the endoscope camera (e.g., CCDcamera) 156, e.g., as may be performed for ex-vivo tracking in opticalcoherence tomography (OCT) pull-back applied to harvested arterialspecimens. OCT is an optical signal acquisition and processing methodthat captures micrometer-resolution, three-dimensional images fromwithin optical scattering media (e.g., biological tissue). In this way,an end position of the device 102 can be visible through the harvestvessel tissue, indicating location during maneuvering and finalpositioning of the device 102. This can be used as an additional way ofregistering different coordinate spaces, harvesting constraints or toindicate ‘no-go’ areas, to prevent damage to the harvested tissue.

The system 100 may include or be employed with other devices and toolsas well. For example, a cauterization tool 166 may include an integratedshape sensing fiber(s) 168. The tool 166 may include an intravascularflexible elongated radio frequency (RF) or laser cauterization devicewhich can act either at a single location or in a spatially distributedfashion along the vessel length. Based on flow/shape measurements fromthe integrated fiber 168, the cauterization manifold (deployableballoon, filter, mesh, or tines) can be (semi-) automatically conformedto the shape of a lumen of the vessel 131 for targeted delivery of RF orphotocoagulation therapy confined to the side branches 162, whilesimultaneously keeping the main vessel lumen patent.

In another embodiment, a shape sensing fiber(s) 170 may be integratedwith a miniature intravascular imaging probe 172 that providesadditional feedback about vessel anatomy and physiology. This probe 172may include photoacoustic sensors 174 that are exquisitely sensitive toblood contrast, ultrasound sensors, infrared sensors for tissuespectroscopy and discrimination of fat and blood from other tissues,etc. The shape and flow sensing fiber feedback can be used to actuatethe motion of a robotically-controlled endoluminal device (not shown)for side-branch cauterization.

Display 118 may permit a user to interact with the workstation 112 andits components and functions, or any other element within the system100. This is further facilitated by an interface 120 which may include akeyboard, mouse, a joystick, a haptic device, or any other peripheral orcontrol to permit user feedback from and interaction with theworkstation 112.

Referring to FIG. 2, a diagram showing a rib cage 218 of a patient 160illustrates an exemplary set up in accordance with one embodiment. Thepatient is depicted without flesh so that internal features can be seen.Below a sternum 208 is a heart 202. A left internal mammary artery(LIMA) 206 and vein 205 are shown running under ribs 204 with numerousbranches 210, which in many instances run below the ribs 204. The LIMA206 needs to be removed from the chest wall to be used in cardiacbypass.

A fiber optic shape sensing device 216 is inserted in the LIMA 206 toaid in the vessel take down during minimally invasive cardiac bypasssurgery. The shape sensing device 216 is introduced into the vessel 206that will be removed and used for bypass grafting. It should beunderstood that the present principles may also be applied to othercommonly used vessels in cardiac bypass or other bypass surgery. In thecase of LIMA 206, the device 216 can be introduced using a hybridsurgical endoluminal approach. The device 216 may include a catheterthat can be introduced through a port or ports in a minimally invasive(MI) surgery and a small incision in the artery can be used to push thedevice 216 into the artery 206.

Once the device 216 is in place, the device 216 will provide informationon the 3D shape of the vessel 206 as well as flow information at eachpoint of an optical fiber(s) in the device 216. The presence of branches210 will remove part of the flow from the main vessel 206, and can thusbe detected with accuracy using optical fiber sensors of the device 216.Specifically, the optical fibers are capable of distributed volumetricflow sensing along their length.

In a single vessel without branch points, the volume flow rate along thelength is continuous and uniform along the vessel centerline understeady state conditions. In the presence of a side-branch, the volumeflow rate will drop along the length of the fiber sensor. Statisticalmethods for change detection can be applied to the distributed volumeflow measurement along the sensor length to identify segments upstreamand downstream of each side-branch location. In this manner, a 3Dreconstruction of the vessel together with the location of the brancheswill be obtained as described above.

For example, an endoscope 214 may be inserted into a port 212 to provideimages of the vessel 206. The shape sensing data may be overlaid in adisplay image to depict branches 210 to enable the surgeon to find andevaluate each branch 210. As this information is dynamic, it is alsopossible to assess the quality of cauterization of arteries as the LIMAtakedown takes place. Thus, the surgeon can know if the branch 210 hasbeen completely sealed in real-time.

The flow and 3D shape information of the vessel 206 is overlaid onto theendoscope images by a registration procedure. In this way, as thesurgeon proceeds to take down the vessel from the chest wall using longinstruments inserted into ports (e.g., 212), the shape of the vessel andthe location of the branches 210 are viewed on the endoscope image toaid the vessel take down and to ensure all branches 210 are cut andsealed appropriately.

There are several registration methods to overlay the vessels on theendoscope image which can be used. For example, a method for augmentedreality in an uncalibrated endoscope video may be employed by overlayingstructures and 3D models from other imaging modalities. This wouldemploy constructing a 3D image of the LIMA vessel from the shape sensinginformation, and indicating the location of branches at the positions ofreduction of flow. This reconstructed 3D vessel would then be overlaidonto the endoscope image.

As the endoscope 214 may be mechanically coupled with a robotic system220 (representatively shown in FIG. 2), a relative position of theendoscope image in the robotic coordinate frame can be derived throughendoscope calibration procedures, known in art. As an alternative tocalibration, which may introduce workflow issues during the surgery, therobotic system 220 can be steered using an un-calibrated method.

Referring to FIG. 3A, an endoscope view of LIMA 302 is shown asindicated with white arrows. Some of its branches are hidden underneathfascia 310. During cardiac bypass surgery, a vessel, such as the LIMA302 is removed from the patient's body and used to bypass anatherosclerotic narrowing in the coronary arteries. An important step ofthis procedure is the take down of the vessel to be used in the bypassgrafting, which is often located in the chest, leg or arm. The vesselneeds to be well preserved during take down to ensure adequate bloodflow after bypass. In minimally invasive cardiac bypass, direct accessto these vessels is not available, and they are removed using longinstruments inserted into ports. These vessels need to have the numerousbranches cut and stapled to stop potential leakage when bypass occurs.As these vessels are often embedded in fat and fascia 310, branches canoften be missed, and so they are inadvertently cut without being stapledor blocked.

Referring to FIG. 3B, another endoscope view of LIMA 302 is shown asindicated with white arrows. An overlay image 306 of the LIMA 302includes signposts 304 and 308 to indicate branches. Using robotguidance or manual guidance, the overlay image 306 with signposts 304and 308 is employed to visualize or target the branches that wouldotherwise be buried or blocked from view by tissue. The overlay image306 is generated using shape sensing feedback from a shape sensingdevice inserted within the LIMA 302.

While embodiments described herein are intended for minimally invasivecoronary artery bypass grafting, other applications and situations arecontemplated where endoscopic surgery is performed on blood vessels oremployed for the removal of a vessel from a patient's body. In addition,the present principles may be employed in other surgical procedures inother parts of the body or in mechanical systems, including but notlimited to training models, engines, plumbing systems, etc.

Referring to FIG. 4, a method for visualizing a branched lumen is shownin accordance with illustrative embodiments. While the branched lumenmay include a blood vessel, it should be understood that the branchedlumen may include other structures as well. For example, the branchedlumen may include other living tissues (e.g., bronchial tubes) ormechanical structures (e.g., plumbing, etc.). The illustrativeembodiments described with respect to FIG. 4 will refer to surgicalprocedures and in particular takedown of a blood vessel. In block 402,after appropriate preparation, a fiber optic shape sensing device isinserted into a lumen of a blood vessel or the like. The fiber opticshape sensing device is positioned into a blood vessel to be harvested.

In block 404, a position of the lumen and locations of branches from thelumen are determined based upon changes to flow in the lumen. Thesechanges are result from strain induced fluctuations measured by thefiber optic shape sensing device. In one embodiment, the geometry and/orshape of the lumen is reconstructed as a three-dimensional structureincluding branches. A statistical method may be employed for detectingchanges in flow along a length of the lumen to detect the branches.

In one embodiment, the blood vessel may be evaluated using a fiber opticshape sensing device to determine a portion of the blood vessel suitablefor a revascularization procedure in block 405. Other criteria for bloodvessel or other lumen selection may also be employed.

In block 406, at least a portion of the lumen is imaged to provide areal-time image. The imaging may be provided using a scope (e.g., anendoscope) with a camera or other imaging device. The scope may beinserted into a patient to collect the image through a port. The scopemay be robotically controlled. In block 208, the real-time image isregistered with the position of the lumen measured by the fiber opticshape sensing device (shape sensing data). In block 410, an overlayimage indicating the position of the lumen and the locations of branchesis generated on the real-time image. This may be rendered on a display.In one embodiment, the lumen includes a branched blood vessel to beharvested for a bypass procedure. The lumen may include branches thatare invisible due to surrounding tissues. The overlay image providessignposts on the overlay at locations of the branches to render thebranches visible in block 412.

In block 414, a tool may be robot-guided to at least one of thelocations of the branches as indicated in the overlay. Once guided to abranch location a plurality of different procedures or operations may becarried out. The robot guidance may employ a visual servoing method tocenter the endoscopic image on the overlay image. The robot or humanguidance may also employ other techniques for tracking the lumen. In oneexample, in block 416, the branches in the lumen as indicated by theoverlay are sealed off. This may include cauterizing, stapling, etc. thebranches of the blood vessel. Since the overlay image is driven by theshape sensing data, which includes branch location information, theoverlay may be updated using the shape sensing data to indicate whetherthe branches have been sealed off in block 418. In block 420, the bloodvessel is harvested and prepared for revascularization in a bypass orother surgical procedure. In block 422, the procedure is continued,e.g., to complete the takedown or other tasks.

In interpreting the appended claims, it should be understood that:

-   -   a) the word “comprising” does not exclude the presence of other        elements or acts than those listed in a given claim;    -   b) the word “a” or “an” preceding an element does not exclude        the presence of a plurality of such elements;    -   c) any reference signs in the claims do not limit their scope;    -   d) several “means” may be represented by the same item or        hardware or software implemented structure or function; and    -   e) no specific sequence of acts is intended to be required        unless specifically indicated.

Having described preferred embodiments for fiber optic sensor guidednavigation for vascular visualization and monitoring (which are intendedto be illustrative and not limiting), it is noted that modifications andvariations can be made by persons skilled in the art in light of theabove teachings. It is therefore to be understood that changes may bemade in the particular embodiments of the disclosure disclosed which arewithin the scope of the embodiments disclosed herein as outlined by theappended claims. Having thus described the details and particularityrequired by the patent laws, what is claimed and desired protected byLetters Patent is set forth in the appended claims.

1. A method for visualizing a branched lumen, comprising: determiningchanges in lumen due to branches as sensed by strain induced in a fiberoptic shape sensing device inserted within the lumen; and indicatinglocations of the branches on a rendering of the lumen, which enables aninstrument to be guided to the locations of the branches as indicated onthe rendering.
 2. The method as recited in claim 1, wherein the lumenincludes a blood vessel and inserting the fiber optic shape sensingdevice includes positioning the fiber optic shape sensing device intothe blood vessel.
 3. The method as recited in claim 1, whereindetermining changes in the lumen includes employing a statistical methodfor detecting changes in flow along a length of the lumen to detect thebranches.
 4. The method as recited in claim 1, wherein indicatinglocations of branches on a rendering of the lumen includes: providing animage of the lumen; generating an overlay on the image of the lumenbased on shape sensing data; and indicating the location of the brancheson the image of the lumen using the overlay.
 5. The method as recited inclaim 4, the overlay enables sealing off the branches in the lumen asindicated by the overlay.
 6. The method as recited in claim 5, furthercomprising updating the overlay using the shape sensing data to indicatewhether the branches have been sealed off.
 7. The method as recited inclaim 1, wherein the lumen includes a branched blood vessel to beharvested for a bypass procedure.
 8. The method as recited in claim 1,wherein the lumen includes branches invisible due to surrounding tissuesand the step of indicating locations of branches on a rendering of thelumen includes providing signposts at locations of the branches, whichare invisible due to surrounding tissues, to reveal their location. 9.The method as recited in claim 1, wherein the lumen includes a bloodvessel and the method further comprises evaluating the blood vesselusing the fiber optic shape sensing device to determine a portion of theblood vessel suitable for a revascularization procedure.
 10. A methodfor visualizing a branched lumen, comprising: determining a position ofa lumen and locations of branches from the lumen based upon changes toflow in the lumen resulting from strain induced fluctuations measured bya fiber optic shape sensing device inserted within the lumen; imaging aportion of the lumen to provide a real-time image; registering thereal-time image with the position of the lumen measured by the fiberoptic shape sensing device; and generating an overlay image indicatingthe position of the lumen and the locations of branches on the real-timeimage.
 11. The method as recited in claim 10, wherein the lumen includesa blood vessel and inserting the fiber optic shape sensing deviceincludes positioning the fiber optic shape sensing device into the bloodvessel.
 12. The method as recited in claim 10, wherein determining aposition of the lumen and locations of branches from the lumen includesemploying a statistical method for detecting changes in flow along alength of the lumen to detect the branches.
 13. The method as recited inclaim 10, wherein imaging a portion of the lumen to provide a real-timeimage is performed using a scope inserted through a port to image theportion of the lumen.
 14. The method as recited in claim 10, thebranches in the lumen as indicated by the overlay are sealed off. 15.The method as recited in claim 14, wherein the branches in the lumen aresealed off by cauterizing or stapling branches of a blood vessel. 16.The method as recited in claim 14, further comprising updating theoverlay using the shape sensing data to indicate whether the brancheshave been sealed off.
 17. The method as recited in claim 10, wherein thelumen includes a branched blood vessel to be harvested for a bypassprocedure.
 18. The method as recited in claim 10, wherein the lumenincludes branches, which are invisible due to surrounding tissues, andthe step of generating an overlay image includes providing signposts onthe overlay at locations of the branches to render the branches visible.19. The method as recited in claim 10, wherein the lumen includes ablood vessel and the method further comprises evaluating the bloodvessel using the fiber optic shape sensing device to determine a portionof the blood vessel suitable for a revascularization procedure.
 20. Themethod as recited in claim 10, further comprising guiding a tool byrobot to at least one of the locations of the branches as indicated inthe overlay.
 21. A system for monitoring a blood vessel, comprising: aprocessor; a memory coupled to the processor; a sensing andinterpretation module stored in the memory and configured to interpretfiber optic shape sensing data from a fiber optic shape sensing deviceinserted in a blood vessel, wherein the shape sensing data comprisesdata indicating blood flow in the blood vessel, enabling monitoring ofchanges in the blood flow to map branches of the blood vessel; an imagegeneration module stored in the memory and configured to generate anoverlay image based on the fiber optic shape sensing data indicating ashape of the blood vessel and locations of the branches from the bloodvessel; and a display configured to render the overlay image over arendering of the blood vessel to provide a guide for visualizing thebranches of the blood vessel.
 22. The system as recited in claim 21,wherein the fiber optic shape sensing device determines the position ofthe blood vessel and the locations of the branches based upon thechanges to the blood flow in the blood vessel resulting from straininduced fluctuations measured by the fiber optic shape sensing device.23. The system as recited in claim 21, wherein the rendering includes animage of the blood vessel collected using an endoscope and the overlayimage is registered with the image of the blood vessel.
 24. The systemas recited in claim 23, further comprising a robot configured to guideone or more tools in accordance with the overlay image.
 25. The systemas recited in claim 24, wherein the robot is guided using a visualservoing method in accordance with the overlay image.
 26. The system asrecited in claim 24, wherein the one or more tools includes a tool toseal off the branches of the blood vessel.
 27. The system as recited inclaim 26, wherein the overlay image is updated to indicate whichbranches have been sealed off.
 28. The system as recited in claim 21,further comprising a statistical method for detecting changes in flowalong a length of the lumen to detect the branches.
 29. The system asrecited in claim 21, wherein the overlay image includes signposts atlocations of the branches to identify locations of the branches.